3.1 The System Requirements Specification (SyRS), specifies the requirements to be satisfied by a system, subsystem, Hardware Configuration Item (HWCI), component or other physical item, and optionally the requirements for
evidence that each requirement has been so satisfied. Requirements pertaining to the system, subsystem or item’s external interfaces may be presented in the SyRS, or alternatively in one or more Interface Requirements Specifications (IRSs) and/or Interface Control Documents (ICDs) invoked by reference from the SyRS.
3.2 The SyRS, possibly supplemented by IRSs and/or ICDs, is commonly used as the basis for acquisition, supply, design and development, verification and acceptance of the system, subsystem or other item. Throughout this
DID, the term “system” may be interpreted to mean "segment", "subsystem", "element", "HWCI", component or other item, as applicable. The resulting document may be titled System Requirements Specification, Segment
Requirements Specification, Component Requirements Specification or similar, as applicable, or a corresponding subject matter – specific name, e.g., “Air Traffic Control System Requirements Specification”, “Requirements
Specification for a Power Supply Module”, etc.